I know that we used to take my youngest nephew (who has just turned 25) into the ladies with us, his brother is nearly 4 years older than him and it wasn't until he was in his teens that he was allowed to take his little brother into the toilet with him. I'd also be wary of how they actually use the urinal.

A girlfriend is divorced & in a new relationship, her now 13 yo son went to the toilet with her new partner about 1 year ago and the new partner was horrified to see the son drop his pants completely to use the urinal. When he told my girlfriend, she was also horrified, as she had expected her x-husband to "educate" her son on the ettiquete of going to public toilets. She had taught him, as best as she could but honestly thought her xh would correct her son if he saw him doing that.

The 13yo has aspergis, so isn't as worldly and knowledgeable as other boys his age and is the sweetest most darling boy in the whole wide world and if anybody ever laid a single finger on him I'd be baying for their blood (so would my DH)!